Knife auto-return assembly for electrosurgical shears

ABSTRACT

A surgical instrument includes an end effector, a handle assembly, a trigger assembly, an input driving body, and a coupling body. The end effector includes a pair of jaws, a knife, and an RF electrode assembly. The input driving body drives the knife between the pre-fired position and the fired position when traveling between the first position and the second position. The engagement body of the trigger assembly drives the input driving body from the first position to the second position when the coupling body is in the engaged position. The input driving body returns to the first position when the coupling body is in the disengaged position. The coupling body moves from the engaged position to the disengaged position is response to the input driving body traveling from the second position to the third position such that the input driving body returns to the first position.

BACKGROUND

A variety of surgical instruments include one or more elements thattransmit RF energy to tissue (e.g., to coagulate or seal the tissue).Some such instruments comprise a pair of jaws that open and close ontissue, with conductive tissue contact surfaces that are operable toweld tissue clamped between the jaws. In open surgical settings, somesuch instruments may be in the form of forceps having a scissor grip.

In addition to having RF energy transmission elements, some surgicalinstruments also include a translating tissue cutting element. Anexample of such a device is the ENSEAL® Tissue Sealing Device by EthiconEndo-Surgery, Inc., of Cincinnati, Ohio. Further examples of suchdevices and related concepts are disclosed in U.S. Pat. No. 6,500,176entitled “Electrosurgical Systems and Techniques for Sealing Tissue,”issued Dec. 31, 2002, the disclosure of which is incorporated byreference herein; U.S. Pat. No. 7,112,201 entitled “ElectrosurgicalInstrument and Method of Use,” issued Sep. 26, 2006, the disclosure ofwhich is incorporated by reference herein; U.S. Pat. No. 7,125,409,entitled “Electrosurgical Working End for Controlled Energy Delivery,”issued Oct. 24, 2006, the disclosure of which is incorporated byreference herein; U.S. Pat. No. 7,169,146 entitled “ElectrosurgicalProbe and Method of Use,” issued Jan. 30, 2007, the disclosure of whichis incorporated by reference herein; U.S. Pat. No. 7,186,253, entitled“Electrosurgical Jaw Structure for Controlled Energy Delivery,” issuedMar. 6, 2007, the disclosure of which is incorporated by referenceherein; U.S. Pat. No. 7,189,233, entitled “Electrosurgical Instrument,”issued Mar. 13, 2007, the disclosure of which is incorporated byreference herein; U.S. Pat. No. 7,220,951, entitled “Surgical SealingSurfaces and Methods of Use,” issued May 22, 2007, the disclosure ofwhich is incorporated by reference herein; U.S. Pat. No. 7,309,849,entitled “Polymer Compositions Exhibiting a PTC Property and Methods ofFabrication,” issued Dec. 18, 2007, the disclosure of which isincorporated by reference herein; U.S. Pat. No. 7,311,709, entitled“Electrosurgical Instrument and Method of Use,” issued Dec. 25, 2007,the disclosure of which is incorporated by reference herein; U.S. Pat.No. 7,354,440, entitled “Electrosurgical Instrument and Method of Use,”issued Apr. 8, 2008, the disclosure of which is incorporated byreference herein; U.S. Pat. No. 7,381,209, entitled “ElectrosurgicalInstrument,” issued Jun. 3, 2008, the disclosure of which isincorporated by reference herein.

Additional examples of electrosurgical cutting instruments and relatedconcepts are disclosed in U.S. Pat. No. 8,939,974, entitled “SurgicalInstrument Comprising First and Second Drive Systems Actuatable by aCommon Trigger Mechanism,” issued Jan. 27, 2015, the disclosure of whichis incorporated by reference herein; U.S. Pat. No. 9,161,803, entitled“Motor Driven Electrosurgical Device with Mechanical and ElectricalFeedback,” issued Oct. 20, 2015, the disclosure of which is incorporatedby reference herein; U.S. Pat. No. 9,877,720, entitled “Control Featuresfor Articulating Surgical Device,” issued Jan. 30, 2018, the disclosureof which is incorporated by reference herein; U.S. Pat. No. 9,402,682,entitled “Articulation Joint Features for Articulating Surgical Device,”issued Aug. 2, 2016, the disclosure of which is incorporated byreference herein; U.S. Pat. No. 9,089,327, entitled “Surgical Instrumentwith Multi-Phase Trigger Bias,” issued Jul. 28, 2015, the disclosure ofwhich is incorporated by reference herein; and U.S. Pat. No. 9,545,253,entitled “Surgical Instrument with Contained Dual Helix ActuatorAssembly,” issued Jan. 17, 2017, the disclosure of which is incorporatedby reference herein.

Some versions of electrosurgical instruments that are operable to severtissue may be selectively used in at least two modes. One such mode mayinclude both severing tissue and coagulating tissue. Another such modemay include just coagulating tissue without also severing the tissue.Yet another mode may include the use of jaws to grasp and manipulatetissue without also coagulating and/or severing the tissue. When aninstrument includes grasping jaws and tissue severing capabilities, theinstrument may also include a feature that ensures full closure of thejaws before the tissue is severed and/or before the electrodes areactivated.

While various kinds of surgical instrument have been made and used, itis believed that no one prior to the inventor(s) has made or used theinvention described in the appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

While the specification concludes with claims which particularly pointout and distinctly claim this technology, it is believed this technologywill be better understood from the following description of certainexamples taken in conjunction with the accompanying drawings, in whichlike reference numerals identify the same elements and in which:

FIG. 1 depicts a perspective view of an exemplary electrosurgicalforceps instrument, where an end effector is in a closed position, wherea resilient arm is in a relaxed position;

FIG. 2 depicts a perspective view of the end effector of FIG. 1 in anopened position, where a translating knife is in a proximal position;

FIG. 3A depicts a side elevational view of the electrosurgical forcepsinstrument of FIG. 1, where the end effector is in the opened position,where the resilient arm is in the relaxed position, and where thetranslating knife of FIG. 2 is in the proximal position;

FIG. 3B depicts a side elevational view of the electrosurgical forcepsinstrument of FIG. 1, where the end effector is in the closed position,where the resilient arm is in the relaxed position, and where thetranslating knife of FIG. 2 is in the proximal position;

FIG. 3C depicts a side elevational view of the electrosurgical forcepsinstrument of FIG. 1, where the end effector is in the closed position,where the resilient arm is in a flexed position, and where thetranslating knife of FIG. 2 is in the proximal position;

FIG. 3D depicts a side elevational view of the electrosurgical forcepsinstrument of FIG. 1, where the end effector is in the closed position,where the resilient arm is in the flexed position, and where thetranslating knife of FIG. 2 is in a distal position;

FIG. 4A depicts a cross-sectional view of the end effector of FIG. 1,taken along line 4-4 of FIG. 1, where the translating knife of FIG. 2 isin the proximal position;

FIG. 4B depicts a cross-sectional view of the end effector of FIG. 1,taken along line 4-4 of FIG. 1, where the translating knife of FIG. 2 isin the distal position;

FIG. 5 depicts a perspective view of another exemplary electrosurgicalforceps instrument, where an end effector is in a closed position, wherea resilient arm is in a relaxed position;

FIG. 6 depicts an exploded perspective view of a handle assembly of theelectrosurgical forceps instrument of FIG. 5;

FIG. 7 depicts a perspective view of a lockout assembly of theelectrosurgical forceps instrument of FIG. 5;

FIG. 8 depicts a cross-sectional view of the lockout assembly of FIG. 7,taken along line 8-8 of FIG. 7;

FIG. 9 depicts a perspective view of a portion of the forceps instrumentof FIG. 5, with a portion of the handle assembly of FIG. 6 omitted forclarity, where the lockout assembly of FIG. 7 is in a lockedconfiguration, where the resilient arm is in the relaxed position;

FIG. 10 depicts a perspective view of a firing assembly of theelectrosurgical forceps instrument of FIG. 5;

FIG. 11 depicts an exploded view of an input drive assembly of thefiring assembly of FIG. 10;

FIG. 12 depicts a perspective view of a rotary drive assembly of thefiring assembly of FIG. 10;

FIG. 13 depicts an exploded perspective view of the rotary driveassembly of FIG. 12;

FIG. 14A depicts a side elevational view of the electrosurgical forcepsinstrument of FIG. 5, where the end effector is in the opened position,where the resilient arm is in the relaxed position, and where atranslating knife of the end effector is in a proximal position;

FIG. 14B depicts a side elevational view of the electrosurgical forcepsinstrument of FIG. 5, where the end effector is in the closed position,where the resilient arm is in the relaxed position, and where thetranslating knife of the end effector is in the proximal position;

FIG. 14C depicts a side elevational view of the electrosurgical forcepsinstrument of FIG. 5, where the end effector is in the closed position,where the resilient arm is in a flexed position, and where thetranslating knife of the end effector is in the proximal position;

FIG. 14D depicts a side elevational view of the electrosurgical forcepsinstrument of FIG. 5, where the end effector is in the closed position,where the resilient arm is in the flexed position, and where thetranslating knife of the end effector is in a distal position;

FIG. 15A depicts a cross-sectional view of a portion of the instrumentof FIG. 5, taken along line 15-15 of FIG. 5, where the resilient arm isin a relaxed position, where the lockout assembly of FIG. 7 is in alocked position, and where the firing assembly of FIG. 10 is in apre-fired position;

FIG. 15B depicts a cross-sectional view of a portion of the instrumentof FIG. 5, taken along line 15-15 of FIG. 5, where the resilient arm isin a flexed position, where the lockout assembly of FIG. 7 is in anunlocked position, and where the firing assembly of FIG. 10 is in thepre-fired position;

FIG. 15C depicts a cross-sectional view of a portion of the instrumentof FIG. 5, taken along line 15-15 of FIG. 5, where the resilient arm isin the flexed position, where the lockout assembly of FIG. 7 is in theunlocked position, and where the firing assembly of FIG. 10 is in afired position;

FIG. 16A depicts a side elevational view of a portion of the instrumentof FIG. 5, with a portion of the handle assembly of FIG. 6 omitted forclarity, where firing assembly is in a first pre-fired position;

FIG. 16B depicts a side elevation view of a portion of the instrument ofFIG. 5, with a portion of the handle assembly of FIG. 6 omitted forclarity, where the firing assembly is in a second pre-fired position;

FIG. 16C depicts a side elevation view of a portion of the instrument ofFIG. 5, with a portion of the handle assembly of FIG. 6 omitted forclarity, where the firing assembly is in a first fired position;

FIG. 16D depicts a side elevation view of a portion of the instrument ofFIG. 5, with a portion of the handle assembly of FIG. 6 omitted forclarity, where the firing assembly is in a second fired position;

FIG. 16E depicts a side elevation view of a portion of the instrument ofFIG. 5, with a portion of the handle assembly of FIG. 6 omitted forclarity, where the firing assembly is in a pre-returned, post-firedposition;

FIG. 16F depicts a side elevational view of a portion of the instrumentof FIG. 5, with a portion of the handle assembly of FIG. 6 omitted forclarity, where the firing assembly is fully returned to the firstpre-fired position;

FIG. 17 depicts a perspective view of another exemplary electrosurgicalforceps instrument, where an end effector is in a closed position, wherea resilient arm is in a relaxed position;

FIG. 18 depicts an exploded perspective view of a handle assembly of theelectrosurgical forceps instrument of FIG. 17;

FIG. 19 depicts a perspective view of a lockout assembly of theelectrosurgical forceps instrument of FIG. 17;

FIG. 20 depicts a cross-sectional view of the lockout assembly of FIG.19, taken along line 20-20 of FIG. 19;

FIG. 21 depicts a perspective view of a portion of the forcepsinstrument of FIG. 17, with a portion of the handle assembly of FIG. 18omitted for clarity, where the lockout assembly of FIG. 19 is in alocked configuration, where the resilient arm is in the relaxedposition;

FIG. 22 depicts a perspective view of a firing assembly of theelectrosurgical forceps instrument of FIG. 17;

FIG. 23 depicts another perspective view of the firing assembly of FIG.22;

FIG. 24 depicts an exploded perspective view of the firing assembly ofFIG. 22;

FIG. 25 depicts an exploded perspective view of a rotary drive assemblyof the firing assembly of FIG. 22;

FIG. 26A depicts a cross-sectional view of a portion of the instrumentof FIG. 17, taken along line 26-26 of FIG. 17, where the resilient armis in a relaxed position, where the lockout assembly of FIG. 19 is in alocked position, and where the firing assembly of FIG. 22 is in apre-fired position;

FIG. 26B depicts a cross-sectional view of a portion of the instrumentof FIG. 17, taken along line 26-26 of FIG. 17, where the resilient armis in a flexed position, where the lockout assembly of FIG. 19 is in anunlocked position, and where the firing assembly of FIG. 22 is in thepre-fired position;

FIG. 26C depicts a cross-sectional view of a portion of the instrumentof FIG. 17, taken along line 26-26 of FIG. 17, where the resilient armis in the flexed position, where the lockout assembly of FIG. 19 is inthe unlocked position, and where the firing assembly of FIG. 22 is in afired position;

FIG. 27A depicts a side elevational view of a portion of the instrumentof FIG. 17, with a portion of the handle assembly of FIG. 18 omitted forclarity, where firing assembly is in a first pre-fired position;

FIG. 27B depicts a side elevation view of a portion of the instrument ofFIG. 17, with a portion of the handle assembly of FIG. 18 omitted forclarity, where the firing assembly is in a second pre-fired position;

FIG. 27C depicts a side elevation view of a portion of the instrument ofFIG. 17, with a portion of the handle assembly of FIG. 18 omitted forclarity, where the firing assembly is in a first fired position;

FIG. 27D depicts a side elevation view of a portion of the instrument ofFIG. 17, with a portion of the handle assembly of FIG. 18 omitted forclarity, where the firing assembly is in a second fired position;

FIG. 27E depicts a side elevation view of a portion of the instrument ofFIG. 17, with a portion of the handle assembly of FIG. 18 omitted forclarity, where the firing assembly is in a third fired position;

FIG. 27F depicts a side elevation view of a portion of the instrument ofFIG. 17, with a portion of the handle assembly of FIG. 18 omitted forclarity, where the firing assembly is in a pre-returned, post-firedposition; and

FIG. 27G depicts a side elevational view of a portion of the instrumentof FIG. 17, with a portion of the handle assembly of FIG. 18 omitted forclarity, where the firing assembly is fully returned to the firstpre-fired position.

The drawings are not intended to be limiting in any way, and it iscontemplated that various embodiments of the technology may be carriedout in a variety of other ways, including those not necessarily depictedin the drawings. The accompanying drawings incorporated in and forming apart of the specification illustrate several aspects of the presenttechnology, and together with the description serve to explain theprinciples of the technology; it being understood, however, that thistechnology is not limited to the precise arrangements shown.

DETAILED DESCRIPTION

The following description of certain examples of the technology shouldnot be used to limit its scope. Other examples, features, aspects,embodiments, and advantages of the technology will become apparent tothose skilled in the art from the following description, which is by wayof illustration, one of the best modes contemplated for carrying out thetechnology. As will be realized, the technology described herein iscapable of other different and obvious aspects, all without departingfrom the technology. Accordingly, the drawings and descriptions shouldbe regarded as illustrative in nature and not restrictive.

I. OVERVIEW OF EXEMPLARY ELECTROSURGICAL FORCEPS

As previously noted, an electrosurgical instrument may include a set ofjaws, with at least one of the jaws being pivotable relative to theother jaw to selectively compress tissue between the jaws. Once thetissue is compressed, electrodes in the jaws may be activated withbipolar RF energy to seal the tissue. In some instances, a cuttingfeature is operable to sever tissue that is clamped between the jaws.For instance, the cutting feature may be actuated before or after the RFenergy has sealed the tissue. Various references that are cited hereinrelate to electrosurgical instruments where the jaws are part of an endeffector at the distal end of an elongate shaft, such that the endeffector and the shaft may be inserted through a port (e.g., a trocar)to reach a site within a patient during a minimally invasive endoscopicsurgical procedure. A handle assembly may be positioned at the proximalend of the shaft for manipulating the end effector. Such a handleassembly may have a pistol grip configuration or some otherconfiguration.

In some instances, it may be desirable to provide an electrosurgicalinstrument that does not have an elongate shaft or handle assemblysimilar to those described in the various references cited herein. Inparticular, it may be desirable to provide an electrosurgical instrumentthat is configured similar to a forceps device, with a scissor grip.Such instruments may be used in a variety of medical procedures. Variousexamples of electrosurgical shears/forceps devices are disclosed in U.S.Pat. No. 9,610,144, entitled “Electrosurgical Hand Shears,” filed Jan.29, 2013, the disclosure of which is incorporated by reference herein.Various other examples of electrosurgical forceps instruments will bedescribed in greater detail below; while other examples will be apparentto those of ordinary skill in the art in view of the teachings herein.

FIGS. 1-4B show an exemplary electrosurgical forceps instrument (100).Instrument (100) includes a handle assembly (130) extending distallyinto an end effector (110). As will be described in greater detailbelow, instrument (100) may be used to grasp, seal, and sever tissuecaptured by end effector (110).

End effector (110) includes a first jaw (112) having a first electrode(113), a second jaw (114) having a second electrode (115), and a knife(120) configured to translate through the first jaw (112) and the secondjaw (114). First jaw (112) and second jaw (114) are pivotably coupledwith each other via pivot pin (118). First jaw (112) and second jaw(114) may pivot between an open position (FIG. 2) and a closed position(FIG. 1) in order to grasp tissue. First and second electrodes (113,115) are positioned on respective jaws (112, 114) such that electrodes(113, 115) face each other when jaws (112, 114) are pivoted into theclosed position. Additionally, each electrode (113, 115) is U-shaped inthe present example, with the bend of the U-shape located near thedistal end of each respective jaw (112, 114), such that each electrode(113, 115) includes two longitudinally extending, laterally spaced-apartlegs extending along the length of each respective jaw (112, 114).Laterally spaced-apart legs of each electrode (113, 115) andcorresponding portions of jaws (112, 114) define an elongate slot (116).Elongate slot (116) is dimensioned to slidably receive knife (120) suchthat knife may translate from a proximal position (FIG. 4A) to a distalposition (FIG. 4B). Knife (120) includes a distal cutting edge (122)configured to sever tissue captured between jaws (112, 114) in theclosed position.

A cable (102) extends proximally from handle assembly (130). Cable (102)is coupled with a control unit (104), which is further coupled with apower source (106). Power source (106) may power control unit (104).Control unit (104) is operable to provide RF power to electrodes (113,115) of jaws (112, 114), to thereby seal tissue suitably capturedbetween jaws (112, 114).

Handle assembly (130) includes a housing (132), and a resilient arm(134). Housing (132) contains an electrode activation assembly (140) anda firing assembly (150). Housing (132) and resilient arm (134) arepivotably coupled with each other via pivot pin (118). Housing (132)extends distally into first jaw (112), while resilient arm (134) extendsdistally into second jaw (114). Housing (132) defines a knife pathway(124) that slidably houses knife (120). Housing (132) includes a fingerring (136) while resilient arm (134) terminates proximally into a thumbring (138). Therefore, the operator may grasp instrument (100) in ascissor grip fashion and pivot resilient arm (134) relative to housing(132) via rings (136, 138) in order to open and close jaws (112, 114).

Resilient arm (134) is sufficiently resilient that arm (134) may flexfrom a relaxed position (FIG. 3B) to a flexed position (FIG. 3C) inresponse to pivoting arm (134) further toward housing (132) when jaws(112, 114) are already in the closed position. Resilient arm (134) isbiased toward the relaxed position. Further pivoting of resilient arm(134) into the flexed position may result in greater closure forcesbetween jaws (112, 114) as compared to pivoting jaws (112, 114) into theclosed position while arm (134) is in the relaxed position. Resilientarm (134) may be suitably resilient such that when resilient arm (134)is pivoted into the flexed position, the closure force between jaws(112, 114) is sufficient such that electrodes (113, 115) may properlyseal tissue grasped between jaws (112, 114). Additionally, the resilientnature of arm may limit the amount of closure force between jaws (112,114) such that jaws (112, 114) may not compress tissue too much,resulting in inadvertent tissue damage. When the operator no longerdesires to compress tissue between jaws (112, 114) to properly sealclamped tissue, the operator may reduce the amount of closure forceapplied to resilient arm (134) such that arm (134) returns to therelaxed state.

Housing (132) slidingly supports an RF trigger (142) of electrodeactivation assembly (140). RF trigger (142) is in communication withcontrol unit (104). RF trigger (142) may be pressed or actuated tocommand control unit (104) to supply RF energy to electrodes (113, 115)of end effector (110). RF trigger (142) may electrically couple withcontrol unit (104) through any suitable components known to a personhaving ordinary skill in the art in view of the teachings herein.

As will be described in greater detail below, firing assembly (150) isconfigured to actuate knife (120) within jaws (112, 114) from a proximalposition to a distal position in order to sever tissue captured betweenjaws (112, 114). Previous firing assemblies for electrosurgical forcepsmay have had a trigger that was a lever arm configured to rotaterelative to a handle assembly to actuate a knife. The lever arm may haveextended away from the handle assembly in order to provide a mechanicaladvantage for actuating knife within jaws (112, 114). However, whenlever arm extends away from handle assembly, it may become difficultrotate lever arm when instrument is flipped such that thumb ring becomesfinger rings and vice versa. In such instances when instrument isflipped, the lever arm may no longer associate with the index/middlefinger for actuating the lever arm.

Therefore, it may be desirable to have a compact firing assembly with atrigger close to the center of housing such that it is easy to actuatefiring assembly with the same finger(s), even when instrument isflipped. Firing assembly (150) of the current example includes a knifetrigger (152) slidably coupled with housing (132) via a slot (135).Trigger (152) is close to the center of housing (132) such that trigger(152) may be easily accessed regardless if instrument (100) is flippedaround. Trigger (152) may actuate relative to housing (132) in order toactuate a knife (120) of end effector (110). In particular, proximaltranslation of trigger (152) results in distal translation of knife(120), while distal translation of trigger (152) results in proximaltranslation of knife (120). Trigger (152) may be biased toward thedistal position such that knife (120) is biased toward the proximalposition.

Trigger (152) may be coupled with knife (120) through any suitablyfiring mechanism assembly as would be apparent to one having ordinaryskill in the art in view of the teachings herein. It should beunderstood that trigger (152) may be selectively actuated at anysuitable time the operator desires. For instance, the operator may grasptissue by pivoting jaws (112, 114) to the closed position, wait adesired amount of time, and fire trigger (152) to actuate knife (120)and sever tissue. Alternatively, the operator may grasp tissue bypivoting jaws (112, 114), release tissue if jaws (112, 114) are notsatisfactorily grasping tissue, re-grasp tissue, and then fire trigger(152) to actuate knife (120) and sever tissue.

FIGS. 3A-4B show an exemplary operation of instrument (100). FIG. 3Ashows jaws (112, 114) of end effector (110) in the opened position.Therefore, resilient arm (134) is pivoted away from housing (132). Asshown in FIG. 3B, when the operator desires to initially grasp andmanipulate tissue, the operator may pivot resilient arm (134) towardhousing (132) such that jaws (112, 114) are pivoted toward the closedposition while resilient arm (134) remains in the relaxed position. Withjaws (112, 114) pivoted toward the closed position, the operator maymanipulate tissue grasped by jaws (112, 114). It should be understoodthat the closure forces imparted on tissue by jaws (112, 114) at thispoint may not be sufficient enough for suitable sealing of tissue via RFenergy provided by electrodes (113, 115).

Next, as shown in FIG. 3C, if the operator desires to apply RF energy tograsped tissue, the operator may further pivot resilient arm (134)toward housing (132) such that resilient arm bends to the flexedposition. As this point, the closure forces imparted on tissue by jaws(112, 114) is sufficient for proper sealing. The operator may thenactuate RF trigger (142) such that electrodes (113, 115) provide RFenergy to grasped tissue. Next, as shown between FIGS. 3C-3D and 4A-4B,the operator may desire to sever tissue captured between jaws (112,114). Therefore, the operator may actuate trigger (152) proximally asshown between FIGS. 3C-3D such that knife (120) actuates distally asshown between FIGS. 4A-4B. Cutting edge (122) may sever tissue capturesbetween jaws (112, 114) as knife (120) actuates distally throughelongate slot (116).

While in the current example, the operator applies RF energy to graspedtissue and then subsequently severs the tissue, the operator mayalternatively sever grasped tissue first, then apply RF energy to thetissue as would be apparent to one of ordinary skill in the art inaccordance with the teachings herein. Alternatively, the operator mayonly seal grasped tissue by applying RF energy, without severing thetissue, as would be apparent to one of ordinary skill in the art inaccordance with the teachings herein. Alternately, the operator may onlysever grasped tissue, without sealing the tissue, as would be apparentto one of ordinary skill in the art in accordance with the teachingsherein. Alternatively, the operator may just grasp tissue, withoutsevering or sealing the tissue, as would be apparent to one of ordinaryskill in the art in accordance with the teachings herein.

II. ALTERNATIVE EXEMPLARY ELECTROSURGICAL FORCEPS

As mentioned above, it may be desirable to have a compact firingassembly with a trigger close to the center of the housing such that itis easy to actuate the firing assembly regardless of whether theinstrument is flipped. Therefore, it may be desirable to have variousfiring assemblies that are configured to convert proximal translation ofa sliding trigger into distal translation of a knife in order to severtissue.

As also mentioned above, resilient arm (134) may flex toward housing(132) when jaws (112, 114) are in the closed position to provide greaterclosure forces between jaws (112, 114). The closure forces provided byflexing resilient arm (134) may help activated electrodes (113, 115)properly seal tissue grasped between jaws (112, 114). During exemplaryuse, if the operator fails to generate enough closure force while jaws(112, 114) are in the closed position, electrodes (113, 115) may fail toproperly seal tissue grasped between jaws (112, 114). Therefore, it maybe desirable to provide a lockout assembly that indicates when jaws(112, 114) provide a suitable closure force for sealing grasped tissueor prevents electrodes (113, 115) from activating unless jaws (112, 114)provide a suitable closure force for sealing grasped tissue.

In some instances, the operator may accidentally actuate knife trigger(152) proximally while jaws (112, 114) are open, inadvertently exposingdistal cutting edge (122) of knife (120) within slot (116). Therefore,it may be desirable to provide a lockout mechanism that preventsactuation of knife until jaws (112, 114) are sufficiently closed.Alternatively, the operator may properly actuate knife (120) distallywhile jaws (112, 114) are suitably grasping tissue, and then prematurelyopen jaws (112, 114) such that distal cutting edge (122) isinadvertently exposed within slot (116). Inadvertent exposure of distalcutting edge (122) within slot (116) while jaws (112, 114) are open maycause accidental tissue damage. Therefore, it may be desirable toprevent exposure of distal cutting edge (122) after distally firingknife (120) through jaws (112, 114) by having an automatic knife returnmechanism configured to automatically drive knife (120) to a pre-firedposition after knife (120) reaches a predetermined distal position.

While various examples of firing assemblies, lockout assemblies, andknife return mechanisms are described below, it should be understoodvarious combinations or modifications may be made to such firingassemblies, lockout assemblies, and knife return mechanism as would beapparent to one having ordinary skill in the art in view of theteachings herein.

A. Exemplary Instrument with Rack and Pinion Firing Assembly, LockoutMechanism, and Knife Return Feature

FIG. 5 shows an alternative exemplary electrosurgical forceps instrument(200) that may be used in replacement of instrument (100) describedabove. Therefore, as will be described in greater detail below,instrument (200) may be used to grasp, seal, and sever tissue.

Instrument (200) includes an end effector (210), a handle assembly(230), an electrode activation assembly (240), a firing assembly (250),and a lockout assembly (290). End effector (210) is substantiallysimilar to end effector (110) described above, with differenceselaborated below. End effector (210) includes a first jaw (212) having afirst electrode (213), a second jaw (214) having a second electrode(215), and a knife (220) configured to translate through the first jaw(212) and the second jaw (214).

First jaw (212) and second jaw (214) are pivotably coupled with eachother via pivot pin (218). First jaw (212) and second jaw (214) maypivot between an open position (FIG. 14A) and a closed position (FIG.14B) in order to grasp tissue. First and second electrodes (213, 215)are positioned on respective jaws (212, 214) such that electrodes (213,215) face each other when jaws (212, 214) are pivoted into the closedposition. Additionally, each electrode (213, 215) is U-shaped in thepresent example, with the bend of the U-shape located near the distalend of each respective jaw (212, 214), such that each electrode (213,215) includes two longitudinally extending, laterally spaced-apart legsextending along the length of each respective jaw (212, 214). Laterallyspaced-apart legs of each electrode (213, 215) and correspondingportions of jaws (212, 214) define an elongate slot (216). Elongate slot(216) is dimensioned to slidably receive knife (220) such that knife maytranslate from a proximal position to a distal position, similar toknife (120) described above. As best shown in FIGS. 6 and 10, knife(220) includes a distal cutting edge (222) configured to sever tissuecaptured between jaws (212, 214) in the closed position.

A cable (202) extends proximally from handle assembly (230). Similar tocable (102) of instrument (100), cable (202) is configured to couplewith control unit (104), which is further coupled with a power source(106). Therefore, control unit (104) is operable to provide RF power toelectrodes (213, 215) of jaws (212, 214), to thereby seal tissuesuitably captured between jaws (212, 214).

Handle assembly (230) includes a housing (232) and a resilient arm(234). Housing (232) and resilient arm (234) are substantially similarto housing (122) and resilient arm (134) described above, withdifferences elaborated below. Housing (232) and resilient arm (234) arepivotably coupled with each other via pivot pin (218). Housing (232)extends distally into first jaw (212), while resilient arm (234) extendsdistally into second jaw (214). Housing defines a knife pathway (224)that slidably houses a portion of knife (220). Housing (232) includes afinger ring (236) while resilient arm (234) terminates proximally into athumb ring (238). Therefore, the operator may grasp instrument (200) ina scissor grip fashion and pivot resilient arm (234) relative to housing(232) via rings (236, 238) in order to open and close jaws (212, 214).

Resilient arm (234) is sufficiently resilient such that arm (234) mayflex from a relaxed position (FIG. 14B) to a flexed position (FIG. 14C)in response to pivoting arm (234) further toward housing (232) when jaws(212, 214) are already in the closed position. Resilient arm (234) isbiased toward the relaxed position. Further pivoting of resilient arm(234) into the flexed position may result in greater closure forcesbetween jaws (212, 214) as compared to pivoting jaws (212, 214) into theclosed position while arm (234) is in the relaxed position. Resilientarm (234) may be suitably resilient such that when resilient arm (234)is pivoted into the flexed position, the closure force between jaws(212, 214) is sufficient such that electrodes (213, 215) may properlyseal tissue grasped between jaws (212, 214). Additionally, the resilientnature of arm (234) may limit the amount of closure force between jaws(212, 214) such that jaws (212, 214) may not compress tissue too much,resulting in inadvertent tissue damage. When the operator no longerdesires to compress tissue between jaws (212, 214) to properly seal orsever clamped tissue, the operator may reduce the amount of closureforce applied to resilient arm (234) such that arm (234) returns to therelaxed position.

Housing (232) contains electrode activation assembly (240), firingassembly (250), and lockout assembly (290). Firing assembly (250) of thecurrent example include a knife trigger (251) slidably coupled withhousing (232) via slot (235). As will be described in greater detailbelow, electrode activation assembly (240) is configured to selectivelyactivate electrodes (213, 215); firing assembly (250) is configured toactuate knife (220) between the proximal position and the distalposition (Similar to knife (120) as shown in FIGS. 4A-4B) in response toproximal translation of knife trigger (251) within slot (235); andlockout assembly (290) is configured to prevent actuation of knife (220)until specific conditions are satisfied. In some examples, lockoutassembly (290) may be configured to prevent activation of electrodes(213, 215) until specific conditions are satisfied, or indicate whenjaws (212, 214) are sufficiently closed for suitably sealing tissue. Aswill also be described in greater detail below, a portion of firingassembly (250) and handle assembly (230) form an automatic knife returnmechanism configured to automatically drive knife (220) to the proximal,pre-fired, position after knife (220) reaches a predetermined distalposition.

Electrode activation assembly (240) includes an RF trigger (242)slidably supported on each lateral side of housing (232), a sliding body(246) slidably contained within housing (232), a coupling block (244)fixed relative to sliding body (246), an activation button (248), and alockout button (245). Coupling block (244) is configured to couple witheach RF trigger (242) when instrument (200) is assembled. A proximal endof sliding body (246) is directly adjacent to activation button (248)such that proximal translation of sliding body (246) triggers activationbutton (248). Therefore, the operator may press RF trigger (242)proximally in order to compress activation button (248). RF trigger(242), coupling block (244), and/or sliding body (246) may be biasedtoward a position such that activation button (248) is not activated.

Activation button (248) and lockout button (245) are each containedwithin housing (232). Lockout button (245) and activation button (248)are each in communication with a circuit board (208) via electricalcoupling wires (205); while circuit board (208) is also in communicationwith at least one electrode (213, 215) via electrical coupling wires(205). In the present example, circuit board (208) is contained withinhousing (232). Circuit board (208) is in communication with cable (202)such that circuit board (208) and control unit (104) are in electricalcommunication with each other. Therefore, circuit board (208) isconfigured to transfer RF energy from control unit (104) to electrodes(213, 215). As will be described in greater detail below, lockoutassembly (290) is configured to depress lockout button (245) when jaws(212, 214) are sufficiently closed to provide sufficient closure forceto properly seal tissue captured between electrodes (213, 215) using RFenergy.

In the present example, activation button (248) and lockout button (245)are configured to instruct circuit board (208) to transfer RF energyfrom control unit (104) to electrodes (213, 215) when buttons (245, 248)are depressed. If only one, or neither, button (245, 248) is depressed,circuit board (208) will not transfer RF energy to electrodes (213,215), thereby leaving electrodes (213, 215) deactivated. Therefore, forexample, if the operator pressed RF trigger (242) without having lockoutbutton (245) depressed, electrodes (213, 215) will remain deactivated.Alternatively, lockout button (245) may act as a switch for activationbutton (248) such that activation of lockout button (245) completes acircuit between at least one electrode (213, 215) and activation button(248).

In another example, lockout button (245) may only generate a signal tocircuit board (208), which may then send the signal to control unit(104), that jaws (212, 214) are sufficiently closed to providesufficient closure force to properly seal tissue captured betweenelectrodes (213, 215) using RF energy. Control unit (104) may thensignal to the operator (e.g., visually, audibly, and/or tactilely) thatjaws (212, 214) are sufficiently closed. In such examples, activationbutton (248) may independently instruct circuit board (208) to transferRF energy from control unit (104) to electrodes (213, 215) whenactivation button (248) is depressed.

In another example, depression of either activation button (248) orlockout button (245) may be configured to activate electrodes (213,215), but activation of buttons (245, 248) may send a different signalto control unit (104), such that control unit produces a differentsignal (e.g., visually, audibly, and/or tactilely) indicating to a userwhich button (245, 248) has been depressed.

In yet another example, activation button (248) may be omitted entirelysuch that pressing lockout button (245) leads to activation ofelectrodes (213, 215).

While in the current example, circuit board (208) acts as anintermediary between control unit (104), electrodes (213, 215), andbuttons (245, 248), this is merely optional, as buttons (245, 248) andelectrodes (213, 215) may be in communication with cable (202) andcontrol unit (104) without the use of circuit board (208).

As mentioned above, lockout assembly (290) is configured to eitherindicate when jaws (212, 214) are sufficiently closed or preventactivation of electrodes (213, 215) until jaws (212, 214) aresufficiently closed; while lockout assembly (290) is also configured toprevent actuation of knife (220) until specific conditions aresatisfied. As best seen in FIGS. 7-8, lockout assembly (290) includes atranslating body (292) defining through holes (295), and a bias spring(298). Translating body (292) includes a button (294) extendingdownwardly from the rest of body (292), and a lockout ledge (296).Translating body (292) is slidably disposed within housing (232).Translating body (292) is configured to actuate between a lockedposition (as shown in FIGS. 9 and 15A) to an unlocked position (as shownin FIGS. 15B-15C); while bias spring (298) abuts against an interiorportion of housing (132) and translating body (292) to bias translatingbody (292) toward the locked position.

As best seen in FIGS. 9 and 15A, a portion of translating body (292)extends away from housing (232) toward thumb ring (238) while in thelocked position. Thumb ring (238) of resilient arm (234) is dimensionedto abut against the portion of translating body (292) extending awayfrom housing (232) when resilient arm (234) is in the flexed position,thereby driving lockout assembly (290) into the unlocked position. Thumbring (238) does not abut against the portion of translating body (292)extending away from housing (232) when resilient arm (234) is in therelaxed position, such that spring (298) biases translating body (292)into the locked position.

As described above, the closure forces provided by jaws (212, 214) whenresilient arm (234) is in the flexed position are suitable forelectrodes (213, 215) to seal tissue via RF energy. Therefore, lockoutassembly (290) is configured to move into the unlocked position whenjaws (212, 214) provide a suitable closure force for electrodes (213,215) to seal tissue via RF energy. Additionally, lockout assembly (290)is configured to move into the locked position when jaws (212, 214) donot provide a suitable closure force for electrodes (213, 215) to sealtissue via RF energy.

While in the unlocked position, button (294) depresses lockout button(245) of electrode activation assembly (240), thereby rendering lockoutbutton (245) activated. Therefore, in the present example, if theoperator presses RF trigger (242) while lockout assembly (290) is in theunlocked position, circuit board (208) would activate electrodes (213,215) due to both buttons (248, 245) being depressed. In other words, theoperator is permitted to activate RF energy to electrodes (213, 215)when the closure forces provided by jaws (212, 214) are suitablyconducive for sealing tissue via RF energy. In another example, lockoutbutton (245) generates a signal send to control unit (104). An in yetanother example, depressing lockout button (245) instructs circuit board(208) to activate electrode (213, 215).

Also, while in the unlocked position, lockout ledge (296) is spaced awayfrom a proximal surface (275) of firing assembly (250) such that firingassembly (250) may actuate knife (220) in accordance with thedescription herein. Therefore, when lockout assembly (290) is in theunlocked position, the operator may both activate electrodes (213, 215)with RF energy, and actuate knife (220) distally to sever tissue graspedbetween jaws (212, 214). Lockout assembly (290) may indicate to theoperator when lockout assembly (290) is in the unlocked configuration.For example, depressing button (245) may activate a suitable indicatoras would be apparent to one having ordinary skill in the art in view ofthe teachings herein. For example, an LED may turn on, an instrument mayemit noise, or a tactile response may be felt.

While in the locked position, button (294) is spaced away from lockoutbutton (245) of electrode activation assembly (240), thereby renderinglockout button (245) un-activated. Therefore, in some versions whereboth lockout button (245) and activation button (238) must be depressedto activate electrodes (213, 215), if the operator presses RF trigger(242) while lockout assembly (290) is in the locked position, eitheraccidentally or in an attempt to provide RF energy to electrodes (213,215), circuit board (208) would not activate electrodes (213, 215) dueto both buttons (248, 245) not being depressed. In other words, theoperator is prevented from activating RF energy to electrodes (213, 215)when the closure forces provided by jaws (212, 214) are not suitablyconducive for sealing tissue via RF energy.

Also, while in the locked position, lockout ledge (296) is directlyadjacent to a proximal surface (275) of firing assembly (250), therebypreventing proximal translation of proximal surface (275) while body(292) is in the locked position. As will be described in greater detailbelow, proximal translation of proximal surface (275) drives distaltranslation of knife (220) in order to sever tissue. Since lockout ledge(296) prevents proximal translation of proximal surface (275) whilelockout assembly (290) is in the locked position, lockout ledge (296)also prevents distal translation of knife (220) while lockout assembly(290) is in the locked position. In other words, when lockout assembly(290) is in the locked position, the operator may be prevented fromactivating electrodes (213, 215) with RF energy, as well as preventedfrom distally actuating knife (220) to sever tissue.

Through holes (295) are dimensioned to allow suitable portions ofelectrode activation assembly (240) and firing assembly (250) to actuatewithin through holes (295). In the current example, one through hole(295) allows sliding body (246) of electrode activation assembly (240)to actuate within through hole (295) to access activation button (248);while another through hole (295) is dimensioned to allow a portion offiring assembly (250) to actuate within through hole (250) whiletranslating body (292) is in the unlocked position. In the currentexample, lockout ledge (296) is housed within a portion of body (292)defining through hole (295), however this is merely optional.

FIGS. 15A-15C show an exemplary use of lockout assembly (290). FIG. 15Ashows resilient arm (234) pivoted toward housing (232) such that jaws(212, 214) are in the closed position while resilient arm (234) is in arelaxed position. Therefore, jaws (212, 214) may not provide asufficient closing force suitable for electrodes (213, 215) to sealtissue grasped by jaws (212, 214). Additionally, thumb ring (238) doesnot abut against translating body (292) such that spring (298) biasestranslating body (292) to the locked position. As mentioned above, sincetranslating body (292) is in the locked position, the operator may notdistally actuate knife (220) or provide RF energy to electrodes (213,215) in accordance with the description herein.

Next, as seen in FIG. 15B, the operator may pivot resilient arm furthertoward housing (232) such that resilient arm bends to the flexedposition. Additionally, thumb ring (238) abuts against translating body(292), overcoming the biasing force provided by spring (298), such thattranslating body (292) is in the unlocked position. At this point, theclosure forces provided by jaws (212, 214) are sufficiently suitably forelectrodes (213, 215) to seal tissue grasped by jaws (212, 214). At thispoint, lockout button (245) is depressed such that lockout button (245)is activated in accordance with the teachings herein. Additionally, asseen in FIG. 15C, while translating body (292) is in the unlockedposition, and operator may actuate trigger (251) of firing assembly(250) such that knife (220) translates distally through elongate slot(216) to sever tissue grasped by jaws (212, 214) in accordance with theteachings herein. Because lockout ledge (296) no longer interferes withproximal translation of proximal surface (275), firing assembly (250)may actuate knife (220) distally. It should be understood that when theoperator no longer presses resilient arm (234) toward housing (232) withenough force to keep arm (234) in the flexed position, the resilientnature of arm (234) will return arm (234) to the relaxed position,allowing spring (298) to bias translating body (292) back into thelocked position.

As mentioned above, firing assembly (250) is configured to convertproximal translation of trigger (251) into distal translation of knife(220). As also mentioned above, a portion of firing assembly (250) andhandle assembly (230) form an automatic knife return mechanismconfigured to automatically drive knife (220) to a pre-fired positionafter knife (220) reaches a predetermined distal position. Firingassembly (250) includes an input drive assembly (270), a rotary driveassembly (252), and an output drive assembly, such as a proximal rack(226) unitarily coupled with knife (220). As will be described ingreater detail below, trigger (251) is configured to actuate input driveassembly (270) proximally such that rotary driver assembly (252)actuates proximal rack (226) and knife (220) distally. It should beunderstood that sliding body (246) of electrode activation assembly(240) may slide independently relative to firing assembly (250).Therefore, the operator may activate electrodes (213, 215) independentlyof firing assembly (250) and knife (220), in accordance with thedescription herein.

Input drive assembly (270) includes a first sliding member (272) and asecond sliding member (280). Both sliding members (272, 280) areslidably contained within housing (232). As will be described in greaterdetail below, first sliding member (272) is configured to proximallydrive second sliding member (280), while second sliding member (280) isconfigured to actuate rotary drive assembly (252).

As best seen in FIG. 11, first sliding member (272) includes a couplingblock (274), a sliding body (276), a pair of laterally spacedprojections (278), proximal surface (275), a grounding pin (273), and abiasing member (271) disposed within the confines of sliding body (276)and against grounding pin (273). Proximal surface (275) is configured toengage lockout assembly (290) is accordance with the teachings herein.Coupling block (274) is fixed relative to sliding body (276). Couplingblock (274) is configured to couple with trigger (251) when instrument(200) is assembled such that actuation of trigger (251) relative tohousing (232) drives actuation of coupling block (274) and sliding body(276) relative to housing (232). As will be described in greater detailbelow, projections (278) are dimensioned to drive portions of secondsliding member (280) proximally in response to proximal translation offirst sliding member (272). Grounding pin (273) is fixed to housing(232) when instrument (200) is assembled such that as sliding body (276)translates, grounding pin (273) remains spatially fixed relative tohousing (232). Biasing member (271) abuts against grounding pin (273)and sliding body (276) in order to bias sliding body (276) to a distal,pre-fired position. Therefore, if the operator actuates trigger (251)proximally, biasing member (271) compresses such that when the operatorreleases trigger (251), biasing member (271) actuates trigger (251) tothe distal, pre-fired, position. In the current example, biasing member(271) includes a spring, but any other suitably biasing member (271) maybe used as would be apparent to one having ordinary skill in the art inview of the teachings herein.

Second sliding member (280) includes a distal rack (282), a sliding body(286), a grounding pin (283), a biasing member (284) disposed within theconfines of sliding body (286), a transverse driving pin (288), and asecond biasing member (287). Distal rack (282) includes a plurality ofteeth (281). As will be described in greater detail below, teeth (281)are configured to mesh with portions of rotary drive assembly (252) suchthat translation of rack (282) rotates rotary drive assembly (252).

Grounding pin (283) is fixed to housing (232) when instrument (200) isassembled such that as sliding body (286) translates, grounding pin(283) remains spatially fixed relative to housing (232). Biasing member(284) abuts against grounding pin (283) and sliding body (286) in orderto bias sliding body (286) to a distal, pre-fired position.

Sliding body (286) defines a slot (289) that slidably houses transversedriving pin (288). Second biasing member (287) biases transverse drivingpin (288) to a downward position within slot (289). Transverse drivingpin (288) may actuate within slot (289) to overcome the biasing force ofsecond biasing member (287). Transverse driving pin (288) is dimensionedto abut against projections (278) of first sliding member (272) when inthe downward position. Therefore, if the operator actuates trigger (251)proximally, first sliding member (272) may proximally drive secondsliding member (280) via projection (278) and transverse driving pin(288). Additionally, as best shown in FIGS. 16A-16F, transverse drivingpin (288) is housed within a slotted pathway (231) defined by theinterior of housing (232). Therefore, as projections (278) drivetransverse driving pin (288), a portion of pin (288) is within slottedpathway (231). As will be described in greater detail below, once firstand second sliding members (272, 280) proximally translate apredetermined distance, transverse driving pin (288) may actuate withinslot (289), due to contact with a cam surface (233) of slotted pathway(231), such that transverse driving pin (288) no longer engagesprojections (278). Therefore, with projections (278) no longer engagingdriving pin (288), first biasing member (284) may distally drive slidingbody (286) and rack (282) back to the distal, pre-fired position, whichin turn may rotate rotary drive assembly (252).

As best shown in FIGS. 12-13, rotary drive assembly (252) includes aninput pinion (254), an output pinion (256), a spacer (258), and a rotarypin (260). Input pinion (254) has a first diameter and includes a firstplurality of teeth (255). Output pinion (256) has a second diameter andincludes a second plurality of teeth (257). The second diameter ofoutput pinion (256) is larger than the first diameter of input pinion(254). Spacer (258) is positioned between input pinion (254) and outputpinion (256). Additionally, input pinion (254), output pinion (256), andspacer (258) each define a locking through hole (264).

Rotary pin (260) is rotatably coupled with housing (232) such thatrotary pin (262) may rotate about its own axis relative to housing (232)but is otherwise fixed relative to housing (232). Rotary pin (260)includes an angular locking body (262) having a flat surface. Angularlocking body (262) is dimensioned with fit through locking through holes(264) of pinions (254, 256) and spacer (258) such that pinions (254,256) and spacer (258) unitarily rotate with rotary pin (260) relative tohosing (232). In other words, if input pinion (254) rotates 90 degreesabout rotary pin (260) in a first angular direction, output pinion (256)also rotates 90 degrees about rotary pin (260) in the first angulardirection.

First plurality of teeth (255) of input pinion (254) are configured tomesh with teeth (281) of distal rack (282) such that translation ofdistal tack (282) causes rotation of input pinion (254). Secondplurality of teeth (257) of output pinion (256) are configured to meshwith teeth (228) of proximal rack (226) such that rotation of outputpinion (256) drives translation of proximal rack (226) and knife (220).As can be seen in FIG. 10 and FIGS. 16A-16F, teeth (255) of input pinion(254) engage teeth (281) of distal rack (282) at one point, while teeth(257) of output pinion (256) engage teeth (228) of proximal tack (226)at a second point, spaced on the opposite side of rotary drive assembly(252). Therefore, proximal movement of input drive assembly (270) anddistal rack (282) may cause rotation of rotary drive assembly (252) in afirst angular direction via meshing of teeth (255, 281). Rotation ofrotary drive assembly (252) in the first angular direction may causedistal movement of knife (220) and proximal rack (226) via meshing ofteeth (257, 228). Alternatively, distal movement of input drive assembly(270) and distal rack (282) may cause rotation of rotary drive assembly(252) in a second angular direction via meshing of teeth (255, 281).Rotation of rotary drive assembly (252) in the second angular directionmay cause proximal movement of knife (220) and proximal rack (226) viameshing of teeth (257, 228).

Because the diameter of output pinion (256) is greater than the diameterof input pinion (254), and because both pinion (254, 256) are configuredto unitarily rotate together, knife (220) and proximal rack (226) maytravel a greater distance than the displacement of distal rack (282) andinput drive assembly (270). This may be advantageous as it may reducethe length the operator has to actuate trigger (251) in order to fireknife (220) distally.

FIGS. 14A-14D and FIGS. 16A-16F show an exemplary use of firing assembly(250) to actuate knife (220) through jaws (212, 214) to sever tissue.First, as shown in FIG. 14A, jaws (212, 214) of end effector (210) inthe opened position. Therefore, resilient arm (234) is pivoted away fromhousing (232). It should be understood that lockout assembly (290) is inthe locked configuration in accordance with the description herein whenresilient arm (234) is in the position shown in FIG. 14A.

Next, as shown in FIG. 14B, when the operator desires to initially graspand manipulate tissue, the operator may pivot resilient arm (234) towardhousing (232) such that jaws (122, 214) are pivoted toward the closedposition while resilient arm (134) remains in the relaxed position. Withjaws (212, 214) pivoted toward the closed position, the operator maymanipulate tissue grasped by jaws (212, 214). It should be understoodthat the closure forces imparted on tissue by jaws (212, 214) at thispoint may not be sufficient enough to suitably seal tissue via RF energyprovided by electrodes (213, 215). Additionally, lockout assembly (290)is in the locked configuration in accordance with the descriptionherein.

Next, as shown in FIG. 14C, if the operator desires to apply RF energyto grasped tissue or sever grasped tissue, the operator may furtherpivot resilient arm (234) toward housing (232) such that resilient armbends to the flexed position. As this point, the closure forces impartedon tissue by jaws (212, 214) is sufficient for proper sealing.Therefore, lockout assembly (290) is moved into the unlockedconfiguration in accordance with the description herein. With lockoutassembly (290) in the unlocked configuration, the operator may activateelectrodes (213, 215) or actuate knife (220) distally through jaws (212,214).

FIGS. 16A-16F show an exemplary actuation of firing assembly (250) inorder to actuate knife (222) from a proximal, pre-fired position,through jaws (212, 214) to a distal position, and back to the proximal,pre-fired position. FIG. 16A shows firing assembly (250) in thepre-fired position. Therefore, knife (220) is in a pre-fired positionsimilar to that shown of knife (120) in FIG. 4A. When the operatordesires to fire knife (220) distally within jaws (212, 214), theoperator may pull trigger (251) proximally. As shown in FIG. 16B, whilepulling trigger (251) proximally, first sliding member (272) may actuateproximally independently of second sliding member (280) untilprojections (278) make contact with transverse driving pin (288).

Next, as shown between FIGS. 14C-14D and FIGS. 16B-16C, the operator mayfurther pull trigger (251) proximally such that first sliding member(272) and second sliding member (280) move proximally together due toprojection (278) making contact with transverse driving pin (288).Therefore, distal rack (282) rotates input pinion (254) and the rest ofrotary drive assembly (252) in the first angular direction due tomeshing of teeth (281, 255). Because input pinion (254) and outputpinion (256) unitarily rotate, output pinion (256) also rotates in thefirst angular direction, which in turn drives knife (220) and proximalrack (226) distally due to meshing of teeth (257, 228). As mentionedabove, knife (220) may translate a further displacement distally thandistal rack (282) translates proximally due the output pinion (256)having a larger diameter than input pinion (254). At the moment shown inFIG. 16C, knife (220) may have actuated substantially through jaws (212,214), severing tissue captured between jaws (212, 214), similar to theposition shown of knife (120) in FIG. 4B.

Because grounding pins (273, 283) are fixed relative to housing (232),movement of sliding bodies (276, 286) compresses biasing members (271,284) between grounding pins (273, 283) and the interior of slidingbodies (276, 286), respectively. As mentioned above, transverse drivingpin (288) is partially housed within slotted pathway (231) definedwithin housing (232). FIG. 16C shows transverse driving pin (288) at aposition just distal to cam surface (233) of slotted pathway (231). Ifthe operator pulls trigger (251) further in the proximal direction, asshown in FIG. 16D, transverse driving pin (288) will come into contactwith cam surface (233) of slotted pathway (231). Cam surface (233) willpush transverse driving pin (288) upwards within slot (289) overcomingthe biasing force of second biasing member (287).

As also shown in FIG. 16D, cam surface (233) may push transverse drivingpin (288) upwards until pin (288) is no longer engaged with projections(278). With pin (288) no longer engaged with projections (278), firstbiasing member (284) may push against grounding pin (283), thereforeactuating second sliding member (280) in the distal direction, as shownin FIG. 16E. Distal actuation of second sliding member (280) causes rack(282) to rotate input pinion (254) in the second angular direction,which in turn rotates output pinion (256) in the second angulardirection, which causes proximal translation of knife (220) and rack(228). In particular, knife (220) may travel all the way back to thepre-fired position. Once actuated proximally past cam surface (233),biasing member (287) may bias transverse pin (288) back within slot(289). Projections (278) may also interact with transverse driving pin(288) and second biasing member (287) such that projections (278) maypush pin (288) upward out of engagement with projections (278) whenknife (220) experiences an excess load, such as when knife (220)encounters an undesirable object. For example, if knife (230) encountersan object difficult to cut, projections (278) may overcome the biasingforce of second biasing member (287) such that transverse driving pin(288) actuates upward within slot (289). In other words, if knife (220)encounters an object too difficult to cut, contact between projections(278) and transverse driving pin (288) may generate a force thatactuates pin (288) within slot (289) such that pin (288) and projection(278) are no longer in engagement, instead of proximally driving secondsliding member (280). Therefore, second sliding member (280) decoupleswith first sliding member (272) prior to knife (220) reaching the firedposition, and knife (220) automatically travels back to the pre-firedposition due to first biasing member (284) driving sliding body (286)distally. This may help prevent knife (220) from being damaged.

It should be understood that second sliding member (280) returns to thepre-fired position even though first sliding member (272) is still inthe fired position. Therefore, once the operator pulls trigger (251) farenough proximally to complete the distal actuation of knife (220),second sliding member (280) may disengage with first sliding member(272) and automatically return knife (220) to the pre-fired position,regardless if the operator holds trigger (251) in the proximal position.In other words, cam surface (233) of slotted pathway (231), transversepin (288), and biasing members (184, 187) may act as an automatic knifereturn mechanism to return knife (220) to the pre-fired poisonautomatically after reaching a predetermined distal location.

As shown between FIGS. 16E-16F, the operator may release trigger (251)such that biasing member (271) pushes first sliding member (272) back tothe position shown in FIG. 16A. The operator may then re-fire knife(220) in accordance with the description herein.

B. Exemplary Instrument with Rotating Arm and Link Firing Assembly,Lockout Mechanism, and Knife Return Feature

FIG. 6 shows an alternative exemplary electrosurgical forceps instrument(300) that may be used in replacement of instrument (100) describedabove. Therefore, as will be described in greater detail below,instrument (300) may be used to grasp, seal, and sever tissue.

Instrument (300) includes an end effector (310), a handle assembly(330), an electrode activation assembly (340), a firing assembly (350),and a lockout assembly (390). End effector (310) is substantiallysimilar to end effector (110) described above, with differenceselaborated below. End effector (310) includes a first jaw (312) having afirst electrode (313), a second jaw (314) having a second electrode(315), and a knife (320) configured to translate through the first jaw(312) and the second jaw (314).

First jaw (312) and second jaw (314) are pivotably coupled with eachother via pivot pin (318). Similar to jaws (112, 114) described above,first jaw (312) and second jaw (314) may pivot between an open positionand a closed position in order to grasp tissue. First and secondelectrodes (313, 315) are positioned on respective jaws (312, 314) suchthat electrodes (313, 315) face each other when jaws (312, 314) arepivoted into the closed position. Additionally, each electrode (313,315) is U-shaped in the present example, with the bend of the U-shapelocated near the distal end of each respective jaw (312, 314), such thateach electrode (313, 315) includes two longitudinally extending,laterally spaced-apart legs extending along the length of eachrespective jaw (312, 314). Laterally spaced-apart legs of each electrode(313, 315) and corresponding portions of jaws (312, 314) define anelongate slot (316). Elongate slot (316) is dimensioned to slidablyreceive knife (320) such that knife may translate from a proximalposition to a distal position, similar to knife (120) described above.As best shown in FIGS. 18 and 22-24, knife (320) includes a distalcutting edge (322) configured to sever tissue captured between jaws(312, 314) in the closed position.

A cable (302) extends proximally from handle assembly (330). Similar tocable (102) of instrument (100), cable (302) is configured to couplewith control unit (104), which is further coupled with a power source(106). Therefore, control unit (104) is operable to provide RF power toelectrodes (313, 315) of jaws (312, 314), to thereby seal tissuesuitably captured between jaws (312, 314).

Handle assembly (330) includes a housing (332) and a resilient arm(334). Housing (332) and resilient arm (334) are substantially similarto housing (122) and resilient arm (134) described above, withdifferences elaborated below. Housing (332) and resilient arm (334) arepivotably coupled with each other via pivot pin (318). Housing (332)extends distally into first jaw (312), while resilient arm (334) extendsdistally into second jaw (314). Housing (332) defines a knife pathway(324) that slidably houses a portion of knife (320). Housing (332)includes a finger ring (336) while resilient arm (334) terminatesproximally into a thumb ring (338). Therefore, the operator may graspinstrument (300) in a scissor grip fashion and pivot resilient arm (334)relative to housing (332) via rings (336, 338) in order to open andclose jaws (312, 314).

Similar to resilient arms (134, 234) described above, resilient arm(334) is sufficiently resilient such that arm (334) may flex from arelaxed position to a flexed position in response to pivoting arm (334)further toward housing (332) when jaws (312, 314) are already in theclosed position. Resilient arm (334) is biased toward the relaxedposition. Further pivoting of resilient arm (334) into the flexedposition may result in greater closure forces between jaws (312, 314) ascompared to pivoting jaws (312, 314) into the closed position while arm(334) is in the relaxed position. Resilient arm (334) may be suitablyresilient such that when resilient arm (334) is pivoted into the flexedposition, the closure force between jaws (312, 314) is sufficient suchthat electrodes (313, 315) may properly seal tissue grasped between jaws(312, 314). Additionally, the resilient nature of arm may limit theamount of closure force between jaws (312, 314) such that jaws (312,314) may not compress tissue too much, resulting in inadvertent tissuedamage. When the operator no longer desires to compress tissue betweenjaws (312, 314) to properly seal or sever clamped tissue, the operatormay reduce the amount of closure force applied to resilient arm (334)such that arm (334) returns to the relaxed state.

Housing (332) contains electrode activation assembly (340), firingassembly (350), and lockout assembly (390). Firing assembly (350) of thecurrent example include a knife trigger (351) slidably coupled withhousing (332) via a slot (335). As will be described in greater detailbelow, electrode activation assembly (340) is configured to selectivelyactivate electrodes (313, 315); firing assembly (350) is configured toactuate knife (320) between the proximal position and the distalposition (Similar to knife (120) as shown in FIGS. 4A-4B) in response toproximal translation of knife trigger (351) within slot (335); andlockout assembly (390) is configured to prevent actuation of knife (320)until specific conditions are satisfied. In some examples, lockoutassembly (390) may be configured to prevent activation of electrodes(313, 315) until specific conditions are satisfied, or indicate whenjaws (212, 214) are sufficiently closed for suitably sealing tissue. Aswill also be described in greater detail below, a portion of firingassembly (350) and handle assembly (330) form an automatic knife returnmechanism configured to automatically drive knife (320) to the proximal,pre-fired, position after knife (320) reaches a predetermined distalposition.

Electrode activation assembly (340) includes an RF trigger (342)slidably supported on each lateral side of housing (332), a sliding body(346) slidably contained within housing (332), a coupling block (344)fixed relative to sliding body (346), an activation button (348), and alockout button (345). Coupling block (344) is configured to couple witheach RF trigger (342) when instrument (300) is assembled. A proximal endof sliding body (346) is directly adjacent to activation button (348)such that proximal translation of sliding body (346) triggers activationbutton (348). Therefore, the operator may press RF trigger (342)proximally in order to compress activation button (348). RF trigger(342), coupling block (344), and/or sliding body (346) may be biasedtoward a position such that activation button (348) is not activated.

Activation button (348) and lockout button (345) are each containedwithin housing (332). Lockout button (345) and activation button (348)are each in communication with a circuit board (308) via electricalcoupling wires (305); while circuit board (308) is also in communicationwith at least one electrode (313, 315) via electrical coupling wires(305). In the present example, circuit board (308) is contained withinhousing (332). Circuit board (308) is in communication with cable (302)such that circuit board (308) and control unit (104) are in electricalcommunication with each other. Therefore, circuit board (308) isconfigured to transfer RF energy from control unit (104) to electrodes(313, 315). As will be described in greater detail below, lockoutassembly (390) is configured to depress lockout button (245) when jaws(312, 314) are sufficiently closed to provide sufficient closure forceto properly seal tissue captured between electrodes (313, 315) using RFenergy.

In the present example, activation button (348) and lockout button (345)are configured to instruct circuit board (308) to transfer RF energyfrom control unit (104) to electrodes (313, 315) when buttons (345, 348)are depressed. If only one, or neither, button (345, 348) is depressed,circuit board (208) will not transfer RF energy to electrodes (313,315), thereby leaving electrodes (313, 315) deactivated. Therefore, forexample, if the operator pressed RF trigger (342) without having lockoutbutton (345) depressed, electrodes (313, 315) will remain deactivated.Alternatively, lockout button (345) may act as a switch for activationbutton (348) such that activation of lockout button (345) completes acircuit between at least one electrode (313, 315) and activation button(348).

In another example, lockout button (345) may only generate a signal tocircuit board (308), which may then send the signal to control unit(104), that jaws (312, 314) are sufficiently closed to providesufficient closure force to properly seal tissue captured betweenelectrodes (313, 315) using RF energy. Control unit (104) may thensignal to the operator (e.g., visually, audibly, and/or tactilely) thatjaws (312, 314) are sufficiently closed. In such examples, activationbutton (348) may independently instruct circuit board (308) to transferRF energy from control unit (104) to electrodes (313, 315) whenactivation button (348) is depressed.

In another example, depression of either activation button (348) orlockout button (345) may activate electrodes (313, 315), but activationof buttons (345, 348) may send a different signal to control unit (104),such that control unit produces a different signal (e.g., visually,audibly, and/or tactilely) indicating to a user which button (345, 348)has been depressed.

In yet another example, activation button (348) may be omitted entirelysuch that pressing lockout button (345) leads to activation ofelectrodes (313, 315).

While in the current example, circuit board (308) acts as anintermediary between control unit (104), electrodes (313, 315), andbuttons (345, 348), this is merely optional, as buttons (345, 348) andelectrodes (313, 315) may be in communication with cable (302) andcontrol unit (104) without the use of circuit board (308).

As mentioned above, lockout assembly (390) is configured to eitherindicate when jaws (312, 314) are sufficiently closed or to preventactivation of electrodes (313, 315) until jaws (312, 314) aresufficiently closed; while lockout assembly (390) is also configured toprevent actuation of knife (320) until specific conditions aresatisfied. As best seen in FIGS. 19-20, lockout assembly (390) includesa translating body (392) defining a through holes (395), and a biasspring (398). Translating body (392) includes a button (394) extendingdownwardly from the rest of body (392), and a lockout ledge (396).Translating body (392) is slidably disposed within housing (332).Translating body (392) is configured to actuate between a lockedposition (as shown in FIGS. 21 and 26A) to an unlocked position (asshown in FIGS. 26B-26C); while bias spring (398) abuts against aninterior portion of housing (332) and translating body (392) to biastranslating body (392) toward the locked position.

As best seen in FIGS. 21 and 26A, a portion of translating body (392)extends away from housing (332) toward thumb ring (338) while in thelocked position. Thumb ring (338) of resilient arm (334) is dimensionedto abut against the portion of translating body (392) extending awayfrom housing (332) when resilient arm (334) is in the flexed position,thereby driving lockout assembly (390) into the unlocked position. Thumbring (338) does not abut against the portion of translating body (392)extending away from housing (332) when resilient arm (334) is in therelaxed position, such that spring (398) biases translating body (392)into the locked position.

As described above, the closure forces provided by jaws (312, 314) whenresilient arm (334) is in the flexed position are suitable forelectrodes (313, 315) to seal tissue via RF energy. Therefore, lockoutassembly (390) is configured to move into the unlocked position whenjaws (312, 314) provide a suitable closure force for electrodes (313,315) to seal tissue via RF energy. Additionally, lockout assembly (390)is configured to move into the locked position when jaws (312, 314) donot provide a suitable closure force for electrodes (313, 315) to sealtissue via RF energy.

While in the unlocked position, button (394) depresses lockout button(345) of electrode activation assembly (340), thereby rendering lockoutbutton (345) activated. Therefore, in the present example, if theoperator presses RF trigger (342) while lockout assembly (390) is in theunlocked position, circuit board (308) would activate electrodes (313,315) dues to both buttons (348, 345) being depressed. In other words,the operator is permitted to activate RF energy to electrodes (313, 315)when the closure forces provided by jaws (312, 314) are suitablyconducive for sealing tissue via RF energy. In another example, lockoutbutton (345) generates a signal send to control unit (104). An in yetanother example, depressing lockout button (345) instructs circuit board(308) to activate electrode (313, 315).

Also, while in the unlocked position, lockout ledge (396) is spaced awayfrom a proximal surface (385) of firing assembly (350) such that firingassembly (350) may actuate knife (320) in accordance with thedescription herein. Therefore, when lockout assembly (390) is in theunlocked position, the operator may both activate electrodes (313, 315)with RF energy, and actuate knife (320) distally to sever tissue graspedbetween jaws (312, 314). Lockout assembly (390) may indicate to theoperator when lockout assembly (390) is in the unlocked configuration.For example, depressing button (345) may activate a suitable indicatoras would be apparent to one having ordinary skill in the art in view ofthe teachings herein. For example, an LED may turn on, a instrument mayemit noise, or a tactile response may be felt.

While in the locked position, button (394) is spaced away from lockoutbutton (345) of electrode activation assembly (340), thereby renderinglockout button (345) un-activated. Therefore, in some versions whereboth lockout button (345) and activation button (338) must be depressedto activate electrodes (313, 315), if the operator presses RF trigger(342) while lockout assembly (390) is in the locked position, eitheraccidentally or in an attempt to provide RF energy to electrodes (313,315), circuit board (308) would not activate electrodes (313, 315) dueto both buttons (348, 345) not being depressed. In other words, theoperator is prevented from activating RF energy to electrodes (313, 315)when the closure forces provided by jaws (312, 314) are not suitablyconducive for sealing tissue via RF energy.

Also, while in the locked position, lockout ledge (396) is directlyadjacent to a proximal surface (385) of firing assembly (350), therebypreventing proximal translation of proximal surface (385) while body(292) is in the locked position. As will be described in greater detailbelow, proximal translation of proximal surface (385) drives distaltranslation of knife (320) in order to sever tissue. Since lockout ledge(396) prevents proximal translation of proximal surface (385) whilelockout assembly (390) is in the locked position, lockout ledge (396)also prevents distal translation of knife (320) while lockout assembly(390) is in the locked position. In other words, when lockout assembly(390) is in the locked position, the operator may be prevented fromactivating electrodes (313, 315) with RF energy, as well as preventedfrom distally actuating knife (320) to sever tissue.

Through hole (395) is dimensioned to allow suitable portions ofelectrode activation assembly (340) and firing assembly (350) to actuatewithin through hole (395). In the current example, through hole (395)allows sliding body (346) of electrode activation assembly (340) toactuate within through hole (395) to access activation button (348).Additionally, through hole (395) is dimensioned to allow a portion offiring assembly (350) to actuate within through hole (350) whiletranslating body (392) is in the unlocked position. In the currentexample, lockout ledge (396) is housed within a portion of body (392)defining through hole (395), however this is merely optional.

FIGS. 26A-26C show an exemplary use of lockout assembly (390). FIG. 26Ashows resilient arm (334) pivoted toward housing (332) such that jaws(312, 314) are in the closed position while resilient arm (334) is in arelaxed position. Therefore, jaws (312, 314) may not provide asufficient closing force suitable for electrodes (313, 315) to sealtissue grasped by jaws (312, 314). Additionally, thumb ring (338) doesnot abut against translating body (392) such that spring (398) biasestranslating body (392) to the locked position. As mentioned above, sincetranslating body (392) is in the locked position, the operator may notdistally actuate knife (320) or provide RF energy to electrodes (313,315) in accordance with the description herein.

Next, as seen in FIG. 26B, the operator may pivot resilient arm furthertoward housing (332) such that resilient arm bends to the flexedposition. Additionally, thumb ring (338) abuts against translating body(392), overcoming the biasing force provided by spring (398), such thattranslating body (392) is in the unlocked position. At this point, theclosure forces provided by jaws (312, 314) are sufficiently suitably forelectrodes (313, 315) to seal tissue grasped by jaws (312, 314). At thispoint, lockout button (345) is depressed such that lockout button (345)is activated in accordance with the teachings herein. Additionally, asseen in FIG. 26C, while translating body (392) is in the unlockedposition, and operator may actuate trigger (351) of firing assembly(350) such that knife (320) translates distally through elongate slot(316) to sever tissue grasped by jaws (312, 314) in accordance with theteachings herein. Because lockout ledge (396) no longer interferes withproximal translation of proximal surface (385), firing assembly (350)may actuate knife (320) distally. It should be understood that when theoperator no longer presses resilient arm (334) toward housing (332) withenough force to keep arm (334) in the flexed position, the resilientnature of arm (334) will return arm (334) to the relaxed position,allowing spring (398) to bias translating body (392) back into thelocked position.

As mentioned above, firing assembly (350) is configured to convertproximal translation of trigger (351) into distal translation of knife(320). As also mentioned above, a portion of firing assembly (350) andhandle assembly (330) form an automatic knife return mechanismconfigured to automatically drive knife (320) to a pre-fired positionafter knife (320) reaches a predetermined distal position. Firingassembly (350) includes an input drive assembly (370), a rotary driveassembly (352), and an output drive assembly, such as a proximal body(326) unitarily coupled with knife (320) and a transverse pin (328)extending laterally from proximal body (326).

As will be described in greater detail below, trigger (351) isconfigured to actuate input drive assembly (370) proximally such thatrotary driver assembly (352) actuates proximal body (326) and knife(220) distally. It should be understood that sliding body (346) ofelectrode activation assembly (340) may slide independently relative tofiring assembly (350). Therefore, the operator may activate electrodes(313, 315) independently of firing assembly (350) and knife (320), inaccordance with the description herein.

Input drive assembly (370) includes a first sliding member (372) and asecond sliding member (380). Both sliding members (372, 380) areslidably contained within housing (332). As will be described in greaterdetail below, first sliding member (372) is configured to proximallydrive second sliding member (380), while second sliding member (380) isconfigured to actuate rotary drive assembly (352).

As best seen in FIGS. 22-24, first sliding member (372) includes acoupling block (374), a sliding body (376), a pair of laterally spacedprojections (378), a grounding pin (373), and a biasing member (371)disposed within the confines of sliding body (376) and against groundingpin (373). Coupling block (374) is fixed relative to sliding body (376).Coupling block (374) is configured to couple with trigger (351) wheninstrument (300) is assembled such that actuation of trigger (351)relative to housing (332) drives actuation of coupling block (374) andsliding body (376) relative to housing (332). As will be described ingreater detail below, projections (378) are dimensioned to driveportions of second sliding member (380) proximally in response toproximal translation of first sliding member (372).

Grounding pin (373) is fixed to housing (332) when instrument (300) isassembled such that as sliding body (376) translates, grounding pin(373) remains spatially fixed relative to housing (332). Biasing member(371) abuts against grounding pin (373) and sliding body (376) in orderto bias sliding body (376) to a distal, pre-fired position. Therefore,if the operator actuates trigger (351) proximally, biasing member (371)compresses such that when the operator releases trigger (351), biasingmember (371) actuates trigger (351) to the distal, pre-fired, position.In the current example, biasing member (371) includes a spring, but anyother suitably biasing member (371) may be used as would be apparent toone having ordinary skill in the art in view of the teachings herein.

Second sliding member (380) includes a distal rack (382), a sliding body(386), a proximal surface (385), a grounding pin (383), a biasing member(384) disposed within the confines of sliding body (386), a transversedriving pin (388), and a second biasing member (387). Proximal surface(385) is configured to engage lockout assembly (390) is accordance withthe teachings above. Distal rack (382) includes plurality of teeth(381). As will be described in greater detail below, teeth (381) areconfigured to mesh with portions of rotary drive assembly (352) suchthat translation of rack (382) rotates rotary drive assembly (352).

Grounding pin (383) is fixed to housing (332) when instrument (300) isassembled such that as sliding body (386) translates, grounding pin(383) remains spatially fixed relative to housing (332). Biasing member(384) abuts against grounding pin (383) and sliding body (386) in orderto bias sliding body (386) to a distal, pre-fired position.

Sliding body (386) defines a slot (389) that slidably houses transversedriving pin (388). Second biasing member (387) biases transverse drivingpin (388) to an upward position within slot (389). Transverse drivingpin (388) may actuate within slot (389) to overcome the biasing force ofsecond biasing member (387). Transverse driving pin (388) is dimensionedto abut against projections (378) of first sliding member (372) when inthe upward position. Therefore, if the operator actuates trigger (351)proximally, first sliding member (372) may proximally drive secondsliding member (380) via projection (378) and transverse driving pin(388). Additionally, as best shown in FIGS. 16A-16F, transverse drivingpin (388) is housed within a slotted pathway (331) defined by theinterior of housing (332). Therefore, as projections (378) drivetransverse driving pin (388), a portion of pin (388) is within slottedpathway (331). As will be described in greater detail below, once firstand second sliding members (372, 380) proximally translate apredetermined distance, transverse driving pin (388) may actuate withinslot (389), due to contact with a cam surface (333) of slotted pathway(331), such that transverse driving pin (388) no longer engagesprojections (378). Therefore, with projections (378) no longer engagingdriving pin (388), first biasing member (384) may distally drive slidingbody (386) and rack (382) back to the distal, pre-fired position, whichin turn may rotate rotary drive assembly (352).

As best seen in FIG. 25, rotary drive assembly (352) includes a rotarygear (354), and a link (356). Rotary gear (354) includes a plurality ofteeth (353), and an arm (355). A central portion of rotary gear (354)defines a through hole (357) while a terminating portion of arm (355)also defines a through hole (359). Rotary gear (354) is rotatablycoupled with housing (332) via pin (358) and through hole (359).Therefore, rotary gear (354) may rotate about pin (358) but is otherwisefixed relative to housing (332). As will be described in greater detailbelow, rotary gear (354) is configured to rotate in response totranslation of distal rack (382) via meshing of teeth (353, 381).

Link (356) defines a though hole (364) near one end of link (356).Additionally, link includes a lateral projection (362) near the oppositeend of link (356) defining through hole (364). Link (356) is pivotablycoupled to both arm (355) of rotary gear (354) and proximal body (326)of knife (320). Link (356) is pivotably coupled to arm (355) via throughholes (364, 259) and a rotary pin (360). Link is pivotably coupled withproximal body (326) of knife (320) via lateral projection (362) and apin hole (325) defined by proximal body (326).

As mentioned above, proximal body (326) of knife (320) includes atransverse pin (328). As best seen in FIGS. 27A-27G, transverse pin(328) is slidably constrained within a second slotted pathway (337) ofhousing (332). Therefore, proximal body (326) must translate along thepath defined by second slotted pathway (337). Since lateral projection(362) of link (356) is pivotably coupled with proximal body (326) ofknife (320), lateral projection (362) is also constrained to translatealong the path defined by second slotted pathway (337). As will bedescribed in greater detail below, because link (356) is rotatablycoupled to arm (355) and proximal body (326) at separate ends of link(354), and because lateral projection (362) is constrained to translatealong the path defined by second slotted pathway (337), rotation ofrotary gear (354) is configured to actuate proximal body (326) and knife(320) along the path defined by second slotted pathway (337).Additionally, the use of link (356) and arm (355) to longitudinallydrive body (326) of knife (320) may cause a knife (320) to travel agreater distance distally than the distance traveled by rack (382)proximally. This may help reduce the size of handle assembly (330).

FIGS. 27A-27G show an exemplary use of firing assembly (350) to actuateknife (320) through jaws (312, 314) to sever tissue. FIG. 27A showsfiring assembly (350) in the pre-fired position whiles jaws (312, 314)are in the closed position and resilient arm is in the flexed position.Therefore, lockout assembly (390) is in the unlocked position, and knife(320) is in a pre-fired position similar to that shown of knife (120) inFIG. 4A. When the operator desires to fire knife (320) distally withinjaws (312, 314), the operator may pull trigger (351) proximally. Asshown between FIGS. 27A-27B, while pulling trigger (351) proximally,first sliding member (372) may actuate proximally independently ofsecond sliding member (380) until projections (378) make contact withtransverse driving pin (388).

Next, as shown between FIGS. 27B-27D, the operator may further pulltrigger (351) proximally such that first sliding member (372) and secondsliding member (380) move proximally together due to projection (378)making contact with transverse driving pin (388). Proximal movement ofsecond sliding member (380) causes rack (382) of second sliding member(380) to rotate rotary gear (354) about pin (358) in a first angulardirection, which in turn causes link (356) to rotate about lateralprojection (362) in a second, opposite, angular direction. Additionally,because lateral projection (362) is pivotably coupled to proximal body(326), and because proximal body (326) is constrained within secondslotted pathway (237), rotation of link (356) about lateral projection(362) in the second angular direction also distally drives proximal body(326) of knife (320). At the moment shown in FIG. 27D, knife (320) mayhave actuated substantially through jaws (312, 314), severing tissuecaptured between jaws (312, 314), similar to the position shown of knife(120) in FIG. 4B.

Because grounding pins (373, 383) are fixed relative to housing (332),movement of sliding bodies (376, 386) compresses biasing members (371,384) between grounding pins (373, 383) and the interior of slidingbodies (376, 386), respectively. As mentioned above, transverse drivingpin (388) is partially housed within slotted pathway (331) definedwithin housing (332). FIG. 27D shows transverse driving pin (388) at aposition just distal to cam surface (333) of slotted pathway (331). Ifthe operator pulls trigger (351) further in the proximal direction, asshown in FIG. 27E, transverse driving pin (388) will come into contactwith cam surface (333) of slotted pathway (331). Cam surface (333) willpush transverse driving pin (388) downwards within slot (389) overcomingthe biasing force of second biasing member (387).

As also shown in FIG. 27E, cam surface (333) may push transverse drivingpin (388) downwards until pin (388) is no longer engaged withprojections (378). With pin (388) no longer engaged with projections(378), first biasing member (384) may push against grounding pin (383),therefore actuating second sliding member (380) in the distal direction,as shown in FIG. 27F. Actuation of second sliding member (380) rotatesrotary gear (354) about pin (358) in the second angular direction, whichin turn causes link (356) to rotate about lateral projection (362) inthe first angular direction such that proximal body (326) is retractedproximally within second slotted pathway (337). In particular, knife(320) may travel all the way back to the pre-fired position. Onceactuated proximally past cam surface (333), biasing member (387) maybias transverse pin (388) back within slot (389). Projections (378) mayalso interact with transverse driving pin (388) and second biasingmember (387) such that projections (378) may push pin (388) downward outof engagement with projections (378) when knife (320) experiences anexcess load, such as when knife (320) encounters an undesirable object.For example, if knife (330) encounters an object difficult to cut,projections (378) may overcome the biasing force of second biasingmember (387) such that transverse driving pin (388) actuates downwardwithin slot (389). In other words, if knife (320) encounters an objecttoo difficult to cut, contact between projections (338) and transversedriving pin (388) may generate a force the actuates pin (388) withinslot (389) such that pin (388) and projection (378) are no longer inengagement, instead of proximally driving second sliding member (380).Therefore, second sliding member (380) decouples with first slidingmember (372) prior to knife (320) reaching the fired position, and knife(320) automatically travels back to the pre-fired position due to firstbiasing member (384) driving sliding body (386) distally. This may helpprevent knife (320) from being damaged.

It should be understood that second sliding member (380) returns to thepre-fired position even though first sliding member (372) is still inthe fired position. Therefore, once the operator pulls trigger (253) farenough proximally to complete the distal actuation of knife (320),second sliding member (380) may disengage with first sliding member(372) and automatically return knife (320) to the pre-fired position,regardless if the operator holds trigger (351) in the proximal position.In other words, cam surface (333) of slotted pathway (331), transversepin (388), and biasing members (384, 387) may act as an automatic knifereturn mechanism to return knife (320) to the pre-fired poisonautomatically after reaching a predetermined distal location.

As shown between FIGS. 27F-27G, the operator may release trigger (351)such that biasing member (371) pushes first sliding member (372) back tothe position shown in FIG. 27A. The operator may then re-fire knife(320) in accordance with the description herein.

III. EXEMPLARY COMBINATIONS

The following examples relate to various non-exhaustive ways in whichthe teachings herein may be combined or applied. It should be understoodthat the following examples are not intended to restrict the coverage ofany claims that may be presented at any time in this application or insubsequent filings of this application. No disclaimer is intended. Thefollowing examples are being provided for nothing more than merelyillustrative purposes. It is contemplated that the various teachingsherein may be arranged and applied in numerous other ways. It is alsocontemplated that some variations may omit certain features referred toin the below examples. Therefore, none of the aspects or featuresreferred to below should be deemed critical unless otherwise explicitlyindicated as such at a later date by the inventors or by a successor ininterest to the inventors. If any claims are presented in thisapplication or in subsequent filings related to this application thatinclude additional features beyond those referred to below, thoseadditional features shall not be presumed to have been added for anyreason relating to patentability.

Example 1

A surgical instrument comprising: (a) an end effector, wherein the endeffector comprises: (i) a first jaw, (ii) a second jaw pivotably coupledwith the first jaw, wherein the second jaw is configured to transitionbetween an open position and a closed position, (iii) a knife configuredto actuate between a pre-fired position and a fired position, and (iv)an electrode assembly configured to apply RF energy to tissue; (b) ahandle assembly, wherein the handle assembly comprises: (i) a housingassociated with the first jaw, and (ii) an arm associated with thesecond jaw, wherein the arm is pivotably coupled with the housing,wherein the arm is configured to pivot the second jaw between the openposition and the closed position; (c) a trigger assembly coupled to thehousing, wherein the trigger assembly comprises an engagement body; (d)an input driving body configured to actuate between a first position, asecond position, and a third position, wherein the input driving body isconfigured to drive the knife between the pre-fired position and thefired position when traveling between the first position and the secondposition, wherein the input driving body is resiliently biased towardthe first position; and (e) a coupling body movably housed within eitherthe input driving body or the trigger assembly, wherein the couplingbody is configured to move between an engaged position and a disengagedposition, wherein the engagement body of the trigger assembly isoperable to drive the input driving body from the first position to thesecond position when the coupling body is in the engaged position,wherein the input driving body is configured to return to the firstposition when the coupling body is in the disengaged position, whereinthe coupling body is operable to move from the engaged position to thedisengaged position in response to the input driving body traveling fromthe second position to the third position such that the input drivingbody returns to the first position.

Example 2

The surgical instrument of Example 1, wherein the input driving bodydefines a slot housing the coupling body.

Example 3

The surgical instrument of Example 2, wherein the coupling body isbiased into the engaged position.

Example 4

The surgical instrument of Example 3, wherein a spring within the slotbiases the coupling body into the engaged position.

Example 5

The surgical instrument of any one or more of Examples 1 through 4,wherein the coupling body comprises a transverse driving pin.

Example 6

The surgical instrument of Example 5, wherein the housing defines aslotted pathway having a camming surface, wherein the driving pin ispartially disposed within the slotted pathway.

Example 7

The surgical instrument of Example 6, wherein the camming surface isoperable to drive the coupling body from the engaged position to thedisengaged position when the input driving body travels from the secondposition to the third position.

Example 8

The surgical instrument of any one or more of Examples 1 through 7,wherein the input driving body comprises a grounding pin attached to thehousing.

Example 9

The surgical instrument of any one or more of Examples 1 through 8,further comprising a rotary assembly, wherein the input driving body isconfigured to rotate the rotary assembly to drive the knife between thepre-fired position and the fired position.

Example 10

The surgical instrument of Example 9, wherein the rotary assemblycomprises a first pinion having a first diameter and a second pinionhaving a second diameter, wherein the second dimeter is greater than thefirst diameter.

Example 11

The surgical instrument of any one or more of Examples 1 through 10,wherein the arm comprises a resilient member configured to transitionbetween a relaxed configuration and a flexed configuration while thesecond jaw is in the closed configuration.

Example 12

The surgical instrument of any one or more of Examples 1 through 11,wherein the engagement body comprises a pair of projections.

Example 13

The surgical instrument of any one or more of Examples 1 through 12,wherein the trigger assembly is biased to a position associated with theknife in a pre-fired position.

Example 14

The surgical instrument of any one or more of Examples 1 through 13,wherein the engagement body is configured to drive the coupling bodyinto the disengaged position prior to reaching the third position inresponse to a predetermined force.

Example 15

A surgical instrument comprising: (a) a housing extending distally intoa first jaw; (b) an arm pivotably coupled with the housing, wherein thearm extends distally into a second jaw, wherein the arm is operable todrive the second jaw between an open position and a closed position; (c)an electrode associated with the first jaw or the second jaw, whereinthe electrode is configured to apply RF energy to tissue; (d) a knifeconfigured to actuate within the first jaw and the second jaw between apre-fired position and a fired position; (e) a trigger assembly coupledto the housing, wherein the trigger assembly comprises an engagementbody; (f) an input driving body configured to actuate between a firstposition, a second position, and a third position, wherein the inputdriving body is configured to drive the knife between the pre-firedposition and the fired position when traveling between the firstposition and the second position, wherein the input driving body isresiliently biased toward the first position; and (g) a coupling bodyslidably housed within either the input driving body or the triggerassembly, wherein the coupling body is configured to move between anengaged position and a disengaged position, wherein the engagement bodyof the trigger assembly is operable to drive the input driving body fromthe first position to the second position when the coupling body is inthe engaged position, wherein the input driving body is configured toreturn to the first position when the coupling body is in the disengagedposition, wherein the engagement body is configured to drive thecoupling body into the disengaged position at a pre-determined forcelimit.

Example 16

The surgical instrument of Example 15, wherein the coupling bodycomprises a transverse pin.

Example 17

The surgical instrument of Example 16, wherein the input driving bodydefines a slot, wherein the transverse pin is slidably housed within theslot.

Example 18

The surgical instrument of Example 17, wherein the transverse pin isbiased by a spring toward the engaged position.

Example 19

The surgical instrument of any one or more of Examples 15 through 17,wherein the trigger assembly comprises a sliding body.

Example 20

A surgical instrument comprising: (a) a housing extending distally intoa first jaw; (b) an arm pivotably coupled with the housing, wherein thearm extends distally into a second jaw, wherein the arm is operable todrive the second jaw between an open position and a closed position; (c)an electrode associated with the first jaw or the second jaw, whereinthe electrode is configured to apply RF energy to tissue; (d) a knifeconfigured to actuate within the first jaw and the second jaw between apre-fired position and a fired position; (e) a trigger assembly movablycoupled to the housing, wherein the trigger assembly comprises anengagement body; (f) an input driving body configured to actuate betweena first position, and a second position, wherein the input driving bodyis configured to drive the knife between the pre-fired position and thefired position when traveling between the first position and the secondposition, wherein the input driving body is biased toward the firstposition; and (g) a coupling body movably housed within either the inputdriving body or the trigger assembly, wherein the coupling body isconfigured to move between an engaged position and a disengagedposition, wherein the input driving assembly is configured to disengagewith the trigger assembly when the coupling body is in the disengagedposition such that the input driving body returns to the first position,wherein the coupling body is operable to selectively travel from theengaged position to the disengaged position.

IV. MISCELLANEOUS

It should also be understood that any one or more of the teachings,expressions, embodiments, examples, etc. described herein may becombined with any one or more of the other teachings, expressions,embodiments, examples, etc. that are described herein. Theabove-described teachings, expressions, embodiments, examples, etc.should therefore not be viewed in isolation relative to each other.Various suitable ways in which the teachings herein may be combined willbe readily apparent to those of ordinary skill in the art in view of theteachings herein. Such modifications and variations are intended to beincluded within the scope of the claims.

Further, any one or more of the teachings, expressions, embodiments,examples, etc. described herein may be combined with any one or more ofthe teachings, expressions, embodiments, examples, etc. described inU.S. App. No. [Atty. Ref. END8550USNP], entitled “Method and Apparatusfor Open Electrosurgical Shears,” filed on even date herewith; U.S. App.No. [Atty. Ref. END8551USNP], entitled “Electrosurgical Shears withKnife Lock and Clamp-Actuated Switch,” filed on even date herewith; U.S.App. No. [Atty. Ref. END8552USNP], entitled “Knife Drive Assembly forElectrosurgical Shears,” filed on even date herewith; U.S. App. No.[Atty. Ref. END8554USNP], entitled “Compound Screw Knife Drive forElectrosurgical Shears,” filed on even date herewith; U.S. App. No.[Atty. Ref. END8555USNP], entitled “Firing and Lockout Assembly forKnife for Electrosurgical Shears,” filed on even date herewith; U.S.App. No. [Atty. Ref. END8556USNP], entitled “Dual Stage EnergyActivation for Electrosurgical Shears,” filed on even date herewith; andU.S. App. No. [Atty. Ref. END8557USNP], entitled “Latching Clamp Arm forElectrosurgical Shears,” filed on even date herewith. The disclosure ofeach of these applications is incorporated by reference herein.

It should be appreciated that any patent, publication, or otherdisclosure material, in whole or in part, that is said to beincorporated by reference herein is incorporated herein only to theextent that the incorporated material does not conflict with existingdefinitions, statements, or other disclosure material set forth in thisdisclosure. As such, and to the extent necessary, the disclosure asexplicitly set forth herein supersedes any conflicting materialincorporated herein by reference. Any material, or portion thereof, thatis said to be incorporated by reference herein, but which conflicts withexisting definitions, statements, or other disclosure material set forthherein will only be incorporated to the extent that no conflict arisesbetween that incorporated material and the existing disclosure material.

Having shown and described various embodiments of the present invention,further adaptations of the methods and systems described herein may beaccomplished by appropriate modifications by one of ordinary skill inthe art without departing from the scope of the present invention.Several of such potential modifications have been mentioned, and otherswill be apparent to those skilled in the art. For instance, theexamples, embodiments, geometrics, materials, dimensions, ratios, steps,and the like discussed above are illustrative and are not required.Accordingly, the scope of the present invention should be considered interms of the following claims and is understood not to be limited to thedetails of structure and operation shown and described in thespecification and drawings.

1-20. (canceled)
 21. A surgical instrument comprising: (a) an endeffector, wherein the end effector comprises: (i) a first jaw, (ii) asecond jaw pivotably coupled with the first jaw, wherein the second jawis configured to transition between an open position and a closedposition, and (iii) a knife configured to actuate between a pre-firedposition and a fired position, wherein the knife is biased toward thepre-fired position; and (b) a firing assembly configured to drive theknife between the pre-fired position and the fired position, wherein thefiring assembly comprises: (i) a trigger assembly configured to actuatebetween a first position, a second position, and a third position,wherein the firing assembly is configured to drive the knife from thepre-fired position toward the fired position in response to the triggerassembly actuating from the first position toward the second position,and (ii) a knife return assembly configured to operatively decouple thetrigger assembly from the knife in response to the trigger assemblyactuating from the second position toward the third position such thatthe knife actuates from the fired position toward the pre-fired positionwhile the trigger assembly remains in the third position.
 22. Thesurgical instrument of claim 21, wherein the end effector comprises afirst electrode surface associated with the first jaw.
 23. The surgicalinstrument of claim 22, wherein the end effector comprises a secondelectrode surface associated with the second jaw.
 24. The surgicalinstrument of claim 23, wherein the first electrode surface and thesecond electrode surface are both U-shaped.
 25. The surgical instrumentof claim 21, wherein the first jaw and the second jaw are pivotallycoupled with each other.
 26. The surgical instrument of claim 21,further comprising a handle assembly, wherein the handle assemblycomprises a housing associated with the first jaw and an arm associatedwith the second jaw.
 27. The surgical instrument of claim 26, whereinthe arm is resilient.
 28. The surgical instrument of claim 26, whereinthe trigger assembly is associated with the housing of the handleassembly.
 29. The surgical instrument of claim 21, wherein the firingassembly further comprise an input pinion and an output pinioninterposed between the trigger assembly and the knife.
 30. The surgicalinstrument of claim 29, wherein the knife return assembly comprises: (i)a rack in communication with the input pinion, (ii) a transverse drivingpin slidably contained within the rack, and (iii) a projectionassociated with the trigger assembly, wherein the projection isconfigured to contact the transverse driving pin in order to drive therack as the trigger assembly actuates from the first position toward thesecond position, and (iv) a cam surface configured to disengage thetransverse driving pin with the projection as the trigger assemblyactuates from the second position toward the third position.
 31. Thesurgical instrument of claim 21, further comprising a lockout assemblyconfigured to inhibit actuation of the knife between the pre-firedposition and the fired position until the second jaw is in the closedposition.
 32. The surgical instrument of claim 21, wherein the triggerassembly is biased toward the first position.
 33. The surgicalinstrument of claim 21, wherein the knife is biased toward the pre-firedposition.
 34. The surgical instrument of claim 21, wherein the firingassembly comprises a rack associated with the knife.
 35. The surgicalinstrument of claim 21, wherein the firing assembly comprises a pinextending through the knife.
 36. A surgical instrument comprising: (a) ahousing extending distally into a first jaw; (b) an arm pivotablycoupled with the housing, wherein the arm extends distally into a secondjaw, wherein the arm is operable to drive the second jaw between an openposition and a closed position; (c) a knife configured to actuate withinthe first jaw and the second jaw between a pre-fired position and afired position, wherein the knife is biased toward the pre-firedposition; (d) a trigger configured to actuate from a first position to asecond position relative to the housing in order to actuate the knifefrom the pre-fired position toward the first position, respectively; and(e) a knife return assembly configured to operatively decouple thetrigger from the knife in response to the knife reaching the firedposition.
 37. The surgical instrument of claim 36, wherein the first jawcomprises a first electrode surface, wherein the second jaw comprises asecond electrode surface, wherein the first electrode surface and thesecond electrode surface are configured to transmit RF energy.
 38. Thesurgical instrument of claim 36, wherein the knife is configured toreturn to the pre-fired position while the trigger remains in the secondposition.
 39. The surgical instrument of claim 36, further comprising aknife actuation assembly interposed between the trigger and the knife.40. A method of using a surgical instrument, the method comprising: (a)pivoting a first jaw toward a second jaw from an open position into aclosed position; (b) pulling a trigger proximally from a first positionto a second position in order to drive a knife distally from a pre-firedposition toward a fired position within the first jaw and the second jawin the closed position, and (c) pulling the trigger further proximallyfrom the second position into a third position such that the knifereturns to the pre-fired position in response to the trigger reachingthe third position.